Malicious PDF — malware analysis report

Static analysis result for SHA-256 a5c53d6d7e0d85ad…

MALICIOUS

PDF

85.0 KB Created: 2021-09-04 19:02:17 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: e635986334f84aa0e172e7fbbfd9884b SHA-1: 93e947c69561b63c2354d987915acc942ed2d1ad SHA-256: a5c53d6d7e0d85ad145aaa87b2e8a99dd4bc03872b0cffd1cd051af753ef2224
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The file was identified as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics reveal it functions as a link farm, with numerous URLs pointing to compromised WordPress sites or disposable domains, suggesting a phishing or malware distribution scheme. The PDF's structure and embedded links are designed to lure users to external, untrusted resources.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://cructi.ru/uplcv?utm_term=trabalenguas+para+ni%C3%B1os+para+imprimir+pdf PDF link annotation
    • https://bor-diing.com/upload/files/41608303991.pdfIn PDF document text
    • http://noithatlekhanh.com/Images_upload/files/75485097557.pdfIn PDF document text
    • http://watthaistuttgart.de/userfiles/file/7347484224.pdfIn PDF document text
    • http://apexibd.com/uploads/fck_uploads/file/73595533987.pdfIn PDF document text
    • http://longhornrings.com/clients/0/08/08da48574b41509ac7bedcf2500dc652/File/21911068166.pdfIn PDF document text
    • https://ladangmimpi.com/contents/files/82598965172.pdfIn PDF document text
    • http://melhi68.com/clients/69549/File/kosalo.pdfIn PDF document text
    • https://study-go.info/wp-content/plugins/super-forms/uploads/php/files/4f458336734ba41f0a8062170f530531/fegeposogagopexatol.pdfIn PDF document text
    • https://sitycare.com/FCK-UserFiles/files/dojojo.pdfIn PDF document text
    • https://www.popcaffe.it/wp-content/plugins/super-forms/uploads/php/files/1c97595ea0c0beee4224cd6006dbecc5/87932947806.pdfIn PDF document text
    • http://iideree.org/wp-content/plugins/formcraft/file-upload/server/content/files/1609d5498092a8---tezevi.pdfIn PDF document text
    • https://www.financedeclined.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/16075d20ba8de9---98809302828.pdfIn PDF document text
    • https://pousadamarazul.tur.br/wp-content/plugins/formcraft/file-upload/server/content/files/16097dfe21894d---sunuvasipifumad.pdfIn PDF document text
    • https://storage-in-motion.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ab3f9d7a678---83909672595.pdfIn PDF document text
    • https://ksboutlet.com/file/files/56479179466.pdfIn PDF document text
    • http://avsa.org/sites/default/files/images/files/58778356484.pdfIn PDF document text
    • https://www.adler-leitishofen.de/wp-content/plugins/formcraft/file-upload/server/content/files/160ec4c22727ba---rexuburatarikugatomene.pdfIn PDF document text
    • http://vasset.bg/userfiles/file/81568262710.pdfIn PDF document text
    • https://fjordancv.info/wp-content/plugins/super-forms/uploads/php/files/d611068c279286c1bd163c0373ea4d29/7243418766.pdfIn PDF document text
    • http://karpatskiles.ru/store/files/rawesunem.pdfIn PDF document text
    • http://msslink.ru/userfiles/files/pixawurekelel.pdfIn PDF document text
    • https://maloneslandscape.com/wp-content/plugins/formcraft/file-upload/server/content/files/160f95a37b9438---towozido.pdfIn PDF document text
    • http://kokocurry.gm/userfiles/file/62609715902.pdfIn PDF document text
    • http://www.kidnuri.com/wp-content/plugins/formcraft/file-upload/server/content/files/16085ee559b016---37153909727.pdfIn PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000de54.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE54 20156 bytes
SHA-256: a9aa093c3a62b9f5d7f20b22e196cc973ccecb52ece906518812ebc8f47c9741
font_01_sfnt_off00011262.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11262 11152 bytes
SHA-256: aa31127f108904e0a5247ab3a0cc3138a4d0b7ff051240b0eaba982f4a2926b5
font_02_sfnt_off00012bb5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12BB5 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1